Propelling, tractive, and supporting apparatus



T. vum. PROPELLING, TRACTIVE, AND SUPPORTING APPARATUS. APPLICATION FILED MAR. 4, 1919.

Patented July 20, 1920.

ATTORNEY UNITED STATES PATENT OFFICE.

TRAJAN vein, or GARCHES, FRANCE.

rnoPn'L me, 'rnno'rivn, AND SUPPORTING APPARATUS.

Be it known that I, TRAJAN VUIA, a subject of the King of Roumania, residing at Garches, Seine-et-Oise, France, have invent- "ed certain new and useful Improvements in Propelling, Tractive, and Supporting Apparatus, of which the following is a specification.

This invention consists in improvements having for their object to increase the efliciency of tractive, propelling and supporting apparatus, such as the propellers of flying machines, ships, and the blade wheels of turbines.

For the purpose of increasing the eiriciency of propelling and tractive means, it has been proposed, apart fromeffecting an increase in the diameter and diminishing the speed of rotation, to increase the number of the blades, the pitch of the screw propellers and also to arrange a plurality of propellers one above another on the same axis. Of all the proposed means none has come into practical use.

In making experiments for the purpose of determining the conditions of the working'and efficiency of screw propellers, attention has been paid only to the ratio of the work to the tractive force or to the supported load. In this manner the following law has been established:

WVhen the speed of rotation increases, the tractive force increases as the square, and the work as the cube of the speed.

In order to determine the tractive or supporting effect of screw propellers, a distinction must be made between the function of a screw propeller when it is intended to draw a small load at a high speed (pulling or pushing screw propeller) and the function of a screw propeller intended to draw a great load at a low speed (supporting screw propeller).

On the other hand it is the wing load which is the criterion for determining the load supported per unit of power.

It may thus be said that all inclined planes subjected to rotary motion support per unit of power a load which is the greater the smaller the wing load per unit of carrying surface.

The law above referred to must be completed as follows:

The load supported per unit of power is in inverse proportion to the velocity of ro- Specification of Letters Patent.

Patented July 20, 1920.

1919. Serial No. 280,678.

tation or to the wing load per unit of carrymg surface. i

The supported weight and the wing load per unit of carrying surface increases as the square of the velocity of rotation. The work consumed increases as the cube of said velocity.

The improvement forming the subject matter of the present invention consists in the combination upon one shaft of two propellers or inclined planes and the like havmg different pitches such that the incidence or pitch of the propeller or inclined plane on the exit or exhaust side is 7 5% greater than the incidence or pitch of the propeller on the suction or admission side.

This improvement is general and applies also to screw propellers proper, that is to say, for pushing or pulling purposes, workmg in air or in water, and also to rotary inclined planes as well as to blades of turbines.

The efficiency will be increased only when, according to the present invention, the incidence of the upper blades is appreciably less than that of the lower blades. This increase is the greater the smaller the wing load per unit of carrying surface, that is to say, the screwpropellers become supporting propellers.

It is to be noted that the same phenomenon occurs also when the screw propellers or rotary planes revolve in the same direction as well as when they revolve in opposite directions relatively to one another.

Referring now to the accompanying drawings which illustrate the invention as applied to screw propellers Figure 1 is a view looking at right angles to the axis and showing the length of the blades,

Fig. 2 is an end view of Fig. 1, and

Fig. 8 is a plan of Fig. 1.

The reference letter a indicates a suitable shaft upon which the propellers are mountgreater when the superposed blades or cidence of fourteen degrees, in other words, the pitch of the lower propeller will be 75% higher than that of the upper propeller in order to obtain the greatest degree of efficiency. 1 V

The efiiciency of this arrangement is planes arestaggered relatively to one another in such a manner that the blade or plane having the smallest pitch or smallest incidence is located in advance of the blade or plane having the greater pitch or indidence. According to the present invention the blade having an incidence'of 8 is located in advance of the blade having an incidenoe of 14 by a distance equal to the width of the blade. V

The illustrated embodimentof the invention shows the screw propellers superposed above one another on a vertical axis, but it is to be understood that the reasoning and the improvement set forth hereinbefore are applicable irrespectively of the position of 'theaxis of the screw propellers or rotating swings.

It is also to be understood that the wing surfaces hereinbefore referred to are actual wing surfaces and not surfaces resulting from the projection of the blades or planes upon a plane at right angles to the axis of shaft'of two having difi'erent pitches such that'the inc1- propellers, and generally of rotating in= clined planes as supporting devices, is less than the efficiency of inclined planes having rectilinear motion.

Each experimenter has worked out his own particular 'efliciency, whereas intlie case of inclined planes having rectilinear motion, it-has been planes, to determinean approximately fixed efficiency as regards their action as supporting devices.

The hereinbefore; investigations show and rotating planes have a higher efiiciency than they were thoughtftohave even as regards their action as supporting devices. 7

VVhatIclaimisl I 1.'In propelling, tractive and supporting apparatus such as screw propellers or inclined planes and the like operating in air stated reasonings and and water,'the combination upon one shaftof two propellers 'or inclined planes having different pitches such that the incidence or pitch of the propeller or inclined plane on the exit or exhaust side is 75% greater than the incidence or pitch of therpropeller on the suction or admission'side.

2. In propelling, tractive and supporting apparatus such as screw propellers'or inclined planes and the like operating in air and water the combination upon a vertical propellers or inclined planes dence or pitch of the propeller or inclined plane on the exit or exhaust side is 75% greater than the'incidence or pitch, of the propeller on the suction or admission'side.

In testimony whereofl have signed my name tothis specification.

.TRAJAN VUIA; f

possible, owing to aerothat screw; propellers 

